Recovering waste heat is one way to meet legislated and competitive fuel efficiency requirements for internal combustion engines. A WHR system to recover heat energy generated by an internal combustion engine that would otherwise be lost through cooling and heat rejection is one way to improve engine efficiency. To recover waste heat economically, relatively high temperature sources are the most desirable, such as exhaust gas recirculation (EGR) coolers, pre-charge air coolers (pre-CAC), and exhaust system heat exchangers. Each of these high temperature sources relate to heat in a gas stream, such as exhaust gas and compressed intake gas. In contrast, heat transferred to a coolant system has been of insufficient quality to recover economically. If some of the heat typically rejected to a coolant system could be recovered, then engine efficiency could be improved by using previously unrecoverable heat energy and by reducing the load on an engine cooling system, which then allows for reduced parasitic load from one or more cooling system pumps.